Contents

Data are often grouped in datasets. In SPIDER too. A dataset is a collection of data that somehow belong together. Each dataset has a URI, which gives access to the metadata describing the dataset. The metadata should tell all there is to know about a dataset (see the recommendation Describe datasets with metadata).

Data dumps

Extra data for church buildings in the Netherlands 1800-1970

Data dumps

Getting data

There are many ways in which to allow data to be retrieved. SPIDER supports several standard methods: Directly resolving URIs, downloading files with complete datasets and querying data using SPARQL. Those methods are described below.

However, there are more ways of making data that have HTTP(S) URIs avialable. A simple RESTAPI for example, or a server based on the Linked Data Platform or Linked Data Fragments specifications. The more standard ways of interacting with data are offered, the more useful the data will be to different types of user.

Direct access

Datasets can be used online by requesting URIs. Datasets in Linked Data contain many URIs which can be requested (dereferenced) to access the data identified. An example of such a data URI is http://data.spider-ld.org/kerkennl/data/year1800.
Dereferencing a URI can be done in a web browser, by the command line by using tools like cURL or Wget, through software that is designed to work with web data, or in programming code.

When data are requested by dereferencing a HTTP(S) URI, content negotiation is used to serve the data in the most appropriate format.

Data dumps

Complete datasets can be downloaded from this folder in various RDF formats.

Querying

To make selections of data the query language SPARQL can be used. The URIhttp://data.spider-ld.org/marmotta/sparql/select?query= can be used to issue SPARQL queries on the command line or in programming code. SPIDER offers some graphical user interfaces to execute SPARQL queries and view the results: